Java & DSL Config for the QueueChannel

Also fix some typos in the `mongodb.adoc`

src/reference/asciidoc/channel.adoc

@@ -505,6 +505,38 @@ Since _version 4.0_, it is recommended that `QueueChannel` s are configured to u
 These are generally optimized for this use, when compared with a general message store.
 If the `ChannelMessageStore` is a `ChannelPriorityMessageStore` the messages will be received in FIFO within priority order.
 The notion of priority is determined by the message store implementation.
+For example the Java Configuration for the <<mongodb-priority-channel-message-store>>:
+
+[source,java]
+----
+@Bean
+public BasicMessageGroupStore mongoDbChannelMessageStore(MongoDbFactory mongoDbFactory) {
+    MongoDbChannelMessageStore store = new MongoDbChannelMessageStore(mongoDbFactory);
+    store.setPriorityEnabled(true);
+    return store;
+}
+
+@Bean
+public PollableChannel priorityQueue(BasicMessageGroupStore mongoDbChannelMessageStore) {
+   return new QueueChannel(new MessageGroupQueue(mongoDbChannelMessageStore, "priorityQueue"));
+}
+----
+
+NOTE: Pay attention to the `MessageGroupQueue` class.
+That is a `BlockingQueue` implementation to utilize the `MessageGroupStore` operations.
+
+The same with Java DSL may look like:
+
+[source,java]
+----
+@Bean
+public IntegrationFlow priorityFlow(PriorityCapableChannelMessageStore mongoDbChannelMessageStore) {
+    return IntegrationFlows.from((Channels c) ->
+            c.priority("priorityChannel", mongoDbChannelMessageStore, "priorityGroup"))
+            ....
+            .get();
+}
+----
 
 Another option to customize the QueueChannel environment is provided by the `ref` attribute of the `<int:queue>` sub-element.
 This attribute implies the reference to any `java.util.Queue` implementation.

src/reference/asciidoc/mongodb.adoc

@@ -107,11 +107,11 @@ The default name for the collection stored by the `ConfigurableMongoDbMessageSto
 It is recommended to use this implementation for robust and flexible solutions when messages contain complex data types.
 
 [[mongodb-priority-channel-message-store]]
-==== MongodDB Channel Message Store
+==== MongoDB Channel Message Store
 
 Starting with _version 4.0_, the new `MongoDbChannelMessageStore` has been introduced; it is an optimized `MessageGroupStore` for use in `QueueChannel` s.
 With `priorityEnabled = true`, it can be used in `<int:priority-queue>` s to achieve _priority_ order polling for persisted messages.
-The _priority_ MonogDB document field is populated from the `IntegrationMessageHeaderAccessor.PRIORITY` (`priority`) message header.
+The _priority_ MongoDB document field is populated from the `IntegrationMessageHeaderAccessor.PRIORITY` (`priority`) message header.
 
 In addition, all MongoDB `MessageStore` s now have a `sequence` field for MessageGroup documents.
 The `sequence` value is the result of an `$inc` operation for a simple `sequence` document from the same collection, which is created on demand.
@@ -141,9 +141,9 @@ To configure that scenario, simply extend one message store bean from the other:
 ----
 
 [[mongodb-metadata-store]]
-==== MongodDB Metadata Store
+==== MongoDB Metadata Store
 
-As of _Spring Integration 4.2_, a new MongodDB-based `MetadataStore` (<<metadata-store>>) implementation is available.
+As of _Spring Integration 4.2_, a new MongoDB-based `MetadataStore` (<<metadata-store>>) implementation is available.
 The `MongoDbMetadataStore` can be used to maintain metadata state across application restarts.
 This new `MetadataStore` implementation can be used with adapters such as: